HVAC wiring help

[Dutch445]

i have to look more on how it affects the furnace coming on.,
example would be power goes out, coal stove goes out, nobody home,
and power comes back on , would it affect furnace from coming in
properly. it seemed last week while running the fan the furnace didn't fire.
but i didn't really commit the time needed to verify that as i had some other
things going on at the time.
i'll dig into it this weekend when i have some time to concentrate.
thanks

 

[PILOON]

Just a shot in the dark, but is it possible that there is a 'run on' type circuit thermostatically regulated to provide a cool down period?

 

[Loadstar]

I really don't feel you would have an issue jumping off G. Jump g out at the furnace then shift stat over to heat and see how it does. You could also pull stat off and jump R,W,and G in furnace and see how it does. I don't think there will be an issue.

 

[kenmac]

looks like my furnace uses 1 speed for heat, another for cool,, and the third not used.
here's a pic from the back of the door, sorry if it isn't easy to see:
View attachment 397311

OK, so what u want to do ? You probably have high, med. And low speed.. low speed red, med speed blue, high speed black. High speed usually for cooling,, low speed/ med speed heat.

 

[Coyote machine]

I wouldn't worry about it at all. The furnace wants to extract as much heat as possible from itself for efficiency AND to protect the furnace heat exchanger and other critical components from premature failure. High heat is OK when it's running, not when it's sitting still. Don't defeat the delay, JMHO.

 

[murphy1244]

CM says "I wouldn't worry about it at all. The furnace wants to extract as much heat as possible from itself for efficiency":thumbsup:

That's it exactly. Nothing to do with protecting the exchanger thou.

 

[Coyote machine]

Why you say, 'nothing to do with protecting the heat exchanger'?

 

[murphy1244]

Why you say, 'nothing to do with protecting the heat exchanger'?

Not that fan cycle CM. They have done without out that cycle if it was a less than 80% furnace

 

[yelbike]

Try a different stat. I don't like brand bashing but in my line of work use only Honeywell or white Rodgers. I prefer Honeywell BC of their awesome and quick tech support. Now back to our regular scheduled event.

I really don't see the with the delayed shut down. Its actually a desired feature in this case that you scavenge more heat from your auxiliary heat source.

BTW cm, the heat exchanger is in no way in harms way. Generally they are capable of operating normally near 170f, there no way an auxiliary furnace will have that output if it's in the return duct. Keep in mind I have not seen the installation, so it's an ASSumption.

 

[Loadstar]

Try a different stat. I don't like brand bashing but in my line of work use only Honeywell or white Rodgers. I prefer Honeywell BC of their awesome and quick tech support. Now back to our regular scheduled event.

I really don't see the with the delayed shut down. Its actually a desired feature in this case that you scavenge more heat from your auxiliary heat source.

BTW cm, the heat exchanger is in no way in harms way. Generally they are capable of operating normally near 170f, there no way an auxiliary furnace will have that output if it's in the return duct. Keep in mind I have not seen the installation, so it's an ASSumption.

I second honeywell stats. Especially their simple models such as a TH5220D1029. Coal miners can beat on them, elderly can figure them out and they are versatile.
I keep recommending hooking up on the low voltage strip because that is where your board is waiting for inputs and how it "knows" what is going on. You will have to get much more complex within the furnace if you take a different path.